[pypy-commit] cffi default: A demo of GMP.

[arigo]

Author: Armin Rigo <arigo at tunes.org>
Branch: 
Changeset: r663:6400958a43dc
Date: 2012-07-17 22:42 +0200
http://bitbucket.org/cffi/cffi/changeset/6400958a43dc/

Log:	A demo of GMP.

diff --git a/demo/gmp.py b/demo/gmp.py
new file mode 100644
--- /dev/null
+++ b/demo/gmp.py
@@ -0,0 +1,30 @@
+import sys
+import cffi
+
+ffi = cffi.FFI()
+
+ffi.cdef("""
+
+    typedef struct { ...; } MP_INT;
+    typedef MP_INT mpz_t[1];
+
+    int mpz_init_set_str (MP_INT *dest_integer, char *src_cstring, int base);
+    void mpz_add (MP_INT *sum, MP_INT *addend1, MP_INT *addend2);
+    char * mpz_get_str (char *string, int base, MP_INT *integer);
+
+""")
+
+lib = ffi.verify("#include <gmp.h>",
+                 libraries=['gmp', 'm'])
+
+# ____________________________________________________________
+
+a = ffi.new("mpz_t")
+b = ffi.new("mpz_t")
+
+lib.mpz_init_set_str(a, sys.argv[1], 10)	# Assume decimal integers
+lib.mpz_init_set_str(b, sys.argv[2], 10)	# Assume decimal integers
+lib.mpz_add(a, a, b)			# a=a+b
+
+s = lib.mpz_get_str(ffi.NULL, 10, a)
+print str(s)